In-situ measurement of bypassing ratio in microporous soil
1997
Lichner, L. (Slovenska Akademia Vied, Bratislava (Slovak Republic). Ustav Hydrobiolgie)
A radioactive trace technique was used in a detailed investigation of water flow and solute transport in the saturated zone of a clay loam soil during small-scale field experiments in a structured clay-loam soil at the Experimental Basis of the Research Institute of Irrigation in Most, near Bratislava (Slovakia), between 1993-1996. After non-ponded infiltration of the radioactive tracer solution (at a rate slightly higher than the matrix saturated hydraulic conductivity) and its redistribution, an easily detectable infiltration front in the soil matrix is formed. Additional infiltration of the non-tagged water (at a rate higher than the matrix-saturated hydraulic conductivity) results in the trace leading edge displacement from which the bypassing ratio can be calculated. An estimation of the bypassing ratio has shown that the macropore flow was about 49 % of the total flow in the barley field in the 1993 experiment, 19 % in the maize field in the 1995 experiment, and 55 % in the untilled soil covered with grass in the 1996 experiment. It can be seen that the warm and rainless second half of April 1993 resulted in nearly as high a macropore flow in the barley field as that in the untilled soil
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